Most contact lenses should not be worn overnight, as it could increase the risk of eye infection. Contacts meant for daily or one-time use can generally be worn up to 14 to 16 hours with no problem, but your doctor … Continue reading →

A simple light microscope manipulates how light enters the eye using a convex lens, where both sides of the lens are curved outwards. When light reflects off of an object being viewed under the microscope and passes through the lens, … Continue reading →

The shorter the lens the wider the angle of view the longer the lens the narrower the angle of view. Besides forming an image a lens controls some of the light entering the camera. A lens is paramount for any … Continue reading →

Once you connected the cameras to the NVR (network video recorder), the cameras will record and save to the NVR without accessing your home router network. No one can hack into the private camera subnet. How do I secure my … Continue reading →

When film negatives are too dark, it likely means it was overexposed. Film speed may have been set too low, shutter speed too slow, or the aperture too wide, or maybe all of the above. It is also possible that … Continue reading →

Samyang’s 16mm f/2 wideangle prime and Canon’s inexpensive compact EF-S 24mm f/2.8 STM are the sharpest primes. What focal length is the sharpest? And you’ll read f/8: both 10 feet and ∞ are sitting above f/8 on the depth-of-field scale. … Continue reading →

Wear your new varifocal glasses as much as possible (even if you’re not used to wearing glasses all the time). The more you wear them, the quicker you will get used to them. Turn your head to point in the … Continue reading →

If well maintained, I’d say 10+ years easy. Lenses tend to become outdated before they actually wear out, and this is one of the reasons that people often recommend focusing on good lenses over a good body. How long should … Continue reading →

purple. The gram negative bacteria will retain their outer cell membrane, and stay purple when your staining is done. Thus both gram positive and negative bacteria will stain purple without the alcohol/acetone step. What would happen if you forgot to … Continue reading →

Focal Length Ilustration If the focal length of two lenses is the same, the lens with the larger diameter will be brighter. For example, if the focal length is 50mm and the lens diameter is 17.8mm, focal length divided by … Continue reading →

Using the teleconverter with a weather-resistant camera, such as the FUJIFILM X-T1 or X-Pro2 mirrorless digital camera and the FUJINON XF50-140mmF2. 8 R LM OIS WR or XF100-400mmF4. Which Fuji lenses are WR? What Fuji Lenses Have Weather Sealing? Lens … Continue reading →

How do you use aperture ring on Nikon? I just realized Nikon DSLRs have a setting that lets you use the aperture ring to set aperture (Custom settings menu –> Customize command dials –> Aperture setting). It only works in … Continue reading →

What is a digital microscope used for? A digital microscope is an efficient tool to inspect and analyze various objects from micro-fabricated parts to large electronic devices. Digital microscopes are used in a wide range of industries, such as education, … Continue reading →

It’s a valid question and the short answer is yes, you can stack lens filters. The longer answer is that it depends on what you’re stacking and the quality of filters you use. Lens filters have different uses and can … Continue reading →

DC DN in sigma lenses is meaning for “DC – lenses” designed for APS-C DLSR cameras. “DN – lenses” designed for compact system cameras. Basically “Sigma” is mainly known as a third-party “lens” manufacturer, producing “lenses” in mounts compatible with … Continue reading →